Radiant Floor Heating/Propane-fired Buderus GB142 problem

QuestionI have a Buderus GB142 boiler heating my house with radiant floor heat. It was installed in 2008 with the propane adapter kit. The first year it worked fine but in the second year it started failing with 6A error codes. The installer contacted the local Buderus rep who recommended cleaning the boiler fins with mineral oil. That took care of the problem for a while but the next year he replaced the flame sensor and cleaned the fins. This year the flame sensor was replaced again and the fins cleaned but I am still getting the 6A failure every few days.
The Buderus people say this boiler has issues running on propane.
They told me that my boiler only had a 2 year warranty even though the current ones have a 5 year warranty.
I saw a video on youtube talking about this boiler having problems with generator power and the solution was to replace the control unit. In the video they changed the controller from version 3.5 to version 3.6
My controller is version 3.5. Do you think upgrading the controller to version 3.6 would help my problem?
Do you have any suggestions on fixing this problem?
Thanks,
Dennis

AnswerPropane is a less-than-ideal fuel, as it often "doped" for weather and other conditions dependent on source, destination and application. When used as a fuel source for any condensing boiler, a combustion test and proper, learned, adjustment, by a Buderus certified technician, is absolutely critical.

As to whether your particular Buderus GB142 will benefit from a new control, I cannot say without a hands-on inspection.

The warranty you speak of is for controls and is quite liberal, as the average warranty, for all but the heat exchanger, is typically one year (more than enough in most cases).

Though we install and service Buderus boilers, including the Gb142, we are leaning toward the relatively new Lambda burner technology, currently only available from Viessmann. This new burner is self-adjusting for fuel quality and looks very promising for this challenging application.

Expertise

Radiant panel heating design, including floors and ceilings, European wall panels and snow melting for residential and light commercial buildings..............................................................-Master of Steam and Hot Water,City of Minneapolis....................................................--- Master Plumber, State of Minnesota...........